The invention relates to a method for stitching patterns, especially for stitching ornamental letters by a sewing machine which is incorporated with a memory storing stitch control data for controlling the stitch to be sewn.
FIG. 3 shows one example of ornamental letter produced by the conventional method using the same type of sewing machine. As shown, the ornamental letter is stitched in such manner that the width X'--X' thereof is formed in the same direction with the lateral swinging movement of the needle and the height Y'--Y' thereof is formed in the same direction with the feeding movement of the fabric feeding device.
As is well known, if the sewing machine is so structured as to provide too much amplitude of the needle swinging transversely of the fabric feeding direction, the property of the sewing machine is generally deteriorated in the straight and other basic stitching operations because of the problem of catching the thread loop by the hook of a loop taker. It is therefore not preferable to enlarge the maximum amplitude W' too much. Accordingly, in case a series of ornamental letters are stitched, it is required to displace the fabric with respect to the needle with interruption of the stitching operation each time one pattern is stitched up, so as to suitably connect the first stitch of the following letter to the last stitch of the preceding letter. It is, however, difficult and time consuming to suitably stitch a series of letters. In any event, the pattern stitching operation is interrupted too many times when a series of ornamental letters are stitched. Further, according to the conventional stitching method, the fabric feeding pitches tend to be minimized for the purpose of giving a letter appearance to the ornamental letters, and such a minimum feeding operation of the feeding device often results in an undesirable formation of stitches due to the property of the fabric feeding device.